The present invention relates to a flashlight and to a method for making same.
Flashlights are available in a wide variety of shapes and sizes, and tailored to a particular use or situation. However, two desires that continue to indicate the need for improved flashlights include the desire for small flashlights and longer useful life. For example, there is a desire for a flashlight that is of a size and shape to conveniently fit in a pocket, e.g., a shirt pocket. In addition, there is a desire for a flashlight that has a bright beam and that operates for a long time before needing to replace or recharge the battery. Also, consumers also want such flashlights to be durable and available at a reasonable cost.
Prior art pocket lights such as a typical pen-shaped light typically are about 1.3 to 2 cm in diameter and are quite heavy, principally due to the size and weight of the type AA (about 1.4 cm diameter) or type AAA (about 1 cm diameter) batteries therein. It would be desirable to have a flashlight of about 1 cm or less in diameter, which is closer to the diameter of typical pens and pencils also kept in a person""s pocket. A further advantage of a smaller-diameter flashlight is the ability to shine the light into small spaces.
The desire for a small-diameter flashlight makes the inclusion of complex internal current-carrying conductors undesirable because they tend to increase the diameter of the light, as well as adding cost thereto, i.e. cost for material, cost for fabrication of the internal parts, and added cost for assembly of the flashlight.
Prior art flashlights typically employ filament-type lamps that have a filament that is electrically heated to glow to produce light, wherein the filament is suspended between supports. Typical filaments tend to be fragile, and often more so when they are heated to glowing. As a filament is used, the filament material may thin or become brittle, thereby increasing its susceptibility to breakage. Even high-light-output lamps such as halogen and xenon lamps employ a heated filament, albeit a more efficient light producer than is a conventional incandescent lamp filament. A solid-state light source, such as a light-emitting diode (LED), for example, does not have a heated filament and so is not subject to the disadvantages associated with lamp filaments, and such LEDs are now available with sufficiently high light output as to be suitable for the light source for a flashlight.
Accordingly, there is a need for a flashlight that can have a small diameter and that has a housing that can be made at a reasonable cost,
To this end, the flashlight of the present invention comprises a cylindrical electrically conductive housing having a reduced inner diameter portion and a hole at a forward end thereof. A solid state light source is in the housing and projects through the hole at the forward end thereof and at least one battery is in the housing. A tail cap is attached to the housing at a rearward end thereof, and a switch selectively connects the solid state light source and the at least one battery in circuit for causing the solid state light source to produce light, the circuit including the electrically conductive housing.
According to another aspect of the invention, a method of making a housing comprises:
providing an elongated hollow member of electrically conductive material having an insulating coating thereon;
forming a reduced inner diameter portion in the elongated hollow member; and
removing the insulating coating from an inner surface of the elongated hollow member in the region of the reduced inner diameter portion thereof.